#include <stdio.h>

int n, m, viz[100005], cnt = 0;

typedef struct nod
{
	int node;			// reprezinta numarul nodului
	nod *next;
} *pNod;
pNod v[100005];

// creaza nodul val
// la dest se afla primul nod din lista de adiacenta a lui x
// &dest reprezinta x
void add(pNod &dest, int val)
{
	pNod p;
	p = new nod;
	p -> node = val;
	p -> next = dest;			// la dest se afla lista de noduri adiacente
	dest = p;					// seteaza p capul listei
}

void citire()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	scanf("%d %d",&n,&m);
	int i, x, y;

	for (i = 1; i <= m; i++)
	{
		scanf("%d %d",&x,&y);
		add(v[x], y);
		add(v[y], x);
	}
}

void dfs(int nod)
{
	viz[nod] = 1;

	for(pNod p = v[nod]; p != NULL; p = p->next)
		if(viz[p->node] == 0)
			dfs(p->node);
}


int main()
{
	citire();
	int i;
	for(int i = 1; i <= n; ++i)
		if(!viz[i])
		{
			cnt++;
			dfs(i);
		}
	printf("%d\n", cnt);

	return 0;
}